There is probably no requirement to carry some form of ID in all places here in the USA, just to walk the streets. But a two-time felon friend-of-mine found out that it is a felony to be without ANY form of ID here in the USA. Maybe he was told that in relation to the state he was in.
I called Thom's show to warn him and the listeners that this 'problem' may actually exist -- and he dropped me like a hot potatoe, and dismissed me as some 'conservative idealogue' or 'plant'. He was 'amazed' that you can be harrassed for some form of ID when merely walking the street. Do not be amazed at such 'police' behavior. You can be pulled over for being "white-and-hippy" as well as being "black" or "mexican" or whatever. There does not need to be some pretense of 'you were doing something wrong', for the police to ask you for your ID. If only we really had a truely "Free-Moving" (the original Libertarian) culture (not the stupid-f**ks that pretend to be 'Libertarian').